A glass-sealed electrode may be used to measure the frequency-dependent complex permittivity of a process fluid mixture at a selected frequency. When used in the oilfield, the electrode may be installed in direct contact with production fluids in topside or subsea applications. The electrode may also be used on tools that are run into a wellbore.
The electrode may include a conductor, a glass insulator, and a metal housing. The glass insulator may have a flat, grinded upper surface configured to be exposed to the process fluid. The flat, grinded upper surface is designed to be flush with a wall of a tubular member (e.g., a pipe) to have optimal contact with the fluid layer. However, the flat, grinded upper surface may lead to defects in the electrode. More particularly, it may lead to cracks in the upper surface of the glass insulator and/or spalling of the glass insulator. As a result, it would be desirable to have an improved electrode that is resistant to cracks and/or spalling.